Recent Trends in Triarylborane Chemistry: Diversification of Structures and Reactivity via meta-Substitution of the Aryl Groups

Abstract This Short Review summarizes the synthesis and applications of triarylboranes (BAr3), including both homoleptic and heteroleptic species, with a focus on the modification of their electronic and structural properties via the introduction of meta-substituents with respect to the B atoms to their Ar groups. This approach constitutes a complementary alternative to conventional strategies for the design of BAr3, which are usually based on a modification of their ortho- and/or para-substituents. An initial analysis revealed that CH3 and F are the most common meta-substituents in hitherto reported BAr3 (apart from the H atom). Thus, an extensive exploration of other substituents, e.g., heavier halogens, longer or functionalized alkyl groups, and aryl groups, will increase our knowledge of the structure and reactivity of BAr3 and eventually lead to a range of new applications. 1 Introduction 2 Scope of this Review 2.1 The Electronic and Steric Influence of meta-Substituents 2.2 Molecular Transformations Mediated by meta-Substituted Boranes 2.3 Other Examples of meta-Functionalization of BAr3 3 Conclusions and Perspectives